Never seen anybody called for it, in any fight, but "pressure points" are still illegal, I think. Tickling probably falls under that.
I do know of a UFC fighter -- he had a few fights in the UFC in the past couple of years -- who probably did some variation of tickling/pressure points in his fights, because I know he did them in classes I was teaching.
He was a chubby kid that showed up to a morning class I was teaching, for beginners, and he said he a couple of fights already and another one booked (for, maybe, a month after he showed up). This was when he only had maybe 4 fights, total. You can never tell what that means, when someone has fought. Sometimes it means their grappling's pretty good, sometimes it doesn't mean their grappling's good at all. I was showing grappling stuff that morning. Anyway, we do the class, and roll for maybe 30 minutes at the end of class, as normally after working on grappling techs. I roll with him and discover that he's pretty good -- feels like a decent blue belt to me, strong and rolling pretty hard with a strong will. I'm stoked, and I think I even did a round robin for him because he said he had a fight booked, to make sure he got some extra work. After class, one student -- also a good friend of mine -- discloses that during the class the guy with 4 fights had taken a knuckle and driven it into his ribs when my buddy/student passed his guard, not in a nice way, and not by accident (same physical move some guys will teach you and call "putting the key in the doorknob" or something like that, to drive the fist under the chin with a digging knuckle to attack a choke -- dirty pool).
It was pretty weird, and I found it funny. In his behavior to me, the 4 fight kid was really respectful and nice, although you could kind of see he was a little bit of a sociopath. It was a weird thing to do to beginners, in a beginner class, for sure.
Anyhow, it would be a major shock to me if he didn't continue to do the "noogie escape" against anybody and everybody, even up to UFC level. But I've never seen anybody called for that, ever, anywhere.
(Sorry but can't tell you the name. What happens in the gym stays in the gym.... I can only tell you he is a crowd pleaser, and you can see he's a little crazy when he fights.)